To my surprise I (lvl33) just got a raidpass from a friendly gym. Thought they were only for lvl 35+ players?
Per Pokemon Go's Twitter page they tweeted this approximately 3 hours ago:
"#PokemonGO - Trainers level 31 and above: You can now participate in Raid Battles at select Gyms around the world. (via @PokemonGoApp)"
I'm level 28 and have fight my first Raid alone today with a Raidpass from a friendly Gym.